John writes:

Dear TWiV,

All y’all have been very helpful in explaining the current pandemic.  Thank you.

A little background: I’m a technologist in Cambridge, England. I do electronics/design chips/write software.   I’ve had an amateur interest in molecular biology since I did A-levels some time in the last millennium. The resources on the internet these days make it much easier to keep up than it used to be. While some folk might watch The Sopranos, I might watch Mr Racaniello’s lecture series on viruses.

This Moderna vaccine seems to be +ssRNA, possibly associated with something resembling a protective nucleocapsid protein (I’m not clear about this part), in a lipid nanoparticle.

  • What is the mechanism of cell attachment and entry? Do the nanoparticles include attachment proteins embedded in the lipid membrane?
  • If there are attachment proteins, is there a risk of an adaptive aka humoral immune response to them ?

Best wishes, and keep up the good work!


Maureen writes:

Professor Racaniello,

I love your show.

I freaked when I saw today’s episode – I love these guys. (See TWiV615, just released, interview with PD in Singapore)

Here’s a video of them from 2004.  It’s short and shows how they go into the field and ‘get it’.

Stay healthy.  Keep teaching.  Maureen

Izzy writes:

Hello TWIVers!

This is a critique of some of the data coming out of the Jenner vaccine trial in monkeys.

Essentially, the issue as I understand it is that the vaccinated monkeys showed differences in amount of viral RNA on bronchoalveolar lavage, but not on nasal swabs. And the titer of neutralizing antibodies was not high. Taken together, this data seems to suggest we can do better. 

Love the podcast and derive a certain level of hipster-like enjoyment in having been a listener since before the days of SARS-CoV-2.

Thank you! 


Ken writes:

Hi crew.

I’ve been listening to V.R.’s lectures and TWIV since early 2018 by a chance discovery, when I found that his lecture series were understandable even to numpties.

Thanks for your considerable labours and please keep it up.

I recently had someone forward an item by Prof. John Ioannidis who espouses that the whole reaction to SARS2 has been overblown and out of proportion to its real threat when compared to similar viruses. He establishes this by an application of Baye’s Theorem of Probability in many of his other works.

This link is his brief outline for the hypothesis:

It’s dated April 3rd 2020 and considerable data has come to light since then that could  be inserted into Baye’s Formula, the basis for this opinion and conclusion.

Can this be used as a valid academic source for conspiracy theorists?

Your comments please? 

Kindest regards,

Ken Parkyn

Brisbane Australia

(we just attained today, exactly one hundred deceased from SARS2, 19th May 2020)

Mason writes:

Hello TWIV folks, from sunny Oviedo Florida (where it’s 73F (23C) at 8 am; though it will be 33C later on). 

Our university is investigating how social distancing might be possible in classrooms by putting small classes into big rooms to enable 6 ft distancing. 

When asked if they had considered airflow, the person in charge of health and safety expressed skepticism that airflow in classrooms had significant effects on the spread of viruses. 

Are they right?  

Are there any studies that can either reassure students and faculty that this isn’t a factor to be concerned about? Or, as I suspect, studies that could help inform our administrators to take airflow into account when deciding how many students a classroom can (relatively) safely accommodate?

Thanks for all you to to bring us such measured and informed (and occasionally very funny) conversations!



Jamison writes:

Alan Dove read my mind when everyone was discussing audio communication services. As a PC gamer I was about to write an email when I heard the program “mumble” mentioned, but then Alan buzzed in with the correct answer which is that mumble is indeed the best audio communication service (gaming or otherwise) with respect to the lowest latency so you can just hear everyone in real time. (Also you touched on the downside which is that you’ll need to find someone to let you use their server or otherwise it’ll come at a premium to host your own.)

Thanks for everything you all do. I’ve been listening for so long I can remember when you all reviewed the movie Contagion in 2012, which at the time I’d watched just so I could listen to the podcast. If you don’t recall you all were very hard on it back then, but I just re-watched and was pleasantly surprised how much (in the current context) it got right for a mainstream movie. I’d say it’s definitely overdue for a revisit.

Anyway, I’m so glad to see this podcast and labor of love getting a fraction of the attention it has always deserved. I’ve shared it with my whole family during the quarantine and my parents are especially appreciative. This continues to be such an invaluable transparent discussion of information between so many well-educated people. Thanks again for all your time and effort.

Best regards,


Aaron writes:

Potential solution to chorus practices *free*

Audio latency is the bread and butter of my existence. I’m *just* an audio engineer and designer of audio recording hardware and software with a lot lot lot of attention paid to the big “L” word

When you are listening to yourself in realtime, by around 13 milliseconds most people notice a small delay (some are much more sensitive) and nearly all people are disturbed by it by 20 milliseconds. 

Even a single sample of latency (1/44,100th of a second at a 44.1khz sample rate) can cause some problems thru phase cancellation if you can hear both the acoustic and the monitored source at once.

However after all that, when playing with others, assuming the instruments aren’t playing too quickly, some people can put up with 50 milliseconds or more of latency providing they are not hearing their own monitored signal, but only the signals of those they are playing along with.

As a however to that however, getting a constant 50 milliseconds across variable and questionable networks is a tricky thing.

NINJAM was created over a decade ago to work out this sort of problem, *for free*. it integrates easily into REAPER as well in the event you want to record it all, or if you would like to use realtime audio processing alongside your virtual choir practice.

NINJAM operates in “faketime” so that all participants are synced to start at exactly the same time, but won’t hear everyone until the second “go round”

“The NINJAM client records and streams synchronized intervals of music between participants. Just as the interval finishes recording, it begins playing on everyone else’s client. So when you play through an interval, you’re playing along with the previous interval of everybody else, and they’re playing along with your previous interval. If this sounds pretty bizarre, it sort of is, until you get used to it, then it becomes pretty natural. In many ways, it can be more forgiving than a normal jam, because mistakes propagate differently.”

Janet writes:

Another choir story  May 17 2020

Eric writes:

Greetings TWIV gang, this is Eric again writing from South Korea. 

We currently have some impressive thunderstorms but otherwise have been enjoying beautiful spring weather of late.

Thanks for answering my previous questions, it has been interesting to see many of the mitigation strategies adopted in the US since then.

New cases have generally been falling here, down to single digits for a couple weeks before there was a cluster with over 100 recently centered in Seoul clubs and bars.  They rapidly tested 45,000 potential contacts and new cases are again trending towards the single digits daily.  As a result, tomorrow schools will begin to reopen, which leads me to my question.  As a high school teacher, I have been following the announced measures being taken at schools throughout Korea including:

1. Opening in phases, with one grade being added each week.

2. Requiring all students and teachers to wear masks.

3. Restricting use of air conditioning and other air circulating machines while keeping windows open for ventilation.

4. Increasing time between classes so students can clean their spaces with alcohol wipes and use the restrooms in small numbers. (Lines are taped on the floor outside restrooms to maintain social distancing for waiting students.)

5. Eating in 15 minute shifts in the cafeteria with all surfaces cleaned between shifts. Students sit in a zigzag pattern with alternate seats empty and plastic dividers have been installed to create individual eating areas.

6. Taking the temperature of each student at least five times per day. (Students have also been completing self-checks for the past two weeks in preparation for returning.)

7. Immediately moving any student with any respiratory symptoms to a special isolation room for evaluation.

8. Requiring students who are or whose family members are possible contacts to stay home for 14 days.

9. Placing antibacterial film on high contact surfaces like light switches and elevator buttons.

There are, of course, other measures.  Our provincial office of education sent teachers a 200 page manual on such procedures.  Again, I wonder if this may be a preview of what American schools will be like in the fall? Many of my students are also worried that these measures might still not be enough to prevent widespread transmission in tightly packed schools with over 1000 students and staff.  Are these measures enough? What else should we consider? And, perhaps more a question for educators and parents than virologists, is this any more sustainable than online lessons? 


Sharon writes:

Greetings Dr. Racaniello, 

Recently, I was surprised to hear about a practice that was recommending maraviroc to all comers with Covid-19 inpatients in a nearby state reporting anecdotal success. After hearing this, I vaguely recalled a brief comment from one of the TWiV podcasts but couldn’t manage to retrace my steps (maybe I dreamed it). I could not find much specifically on maraviroc and it does not seem to be under any active/registered trial on It seemed to be an idea borrowed from leronlimab, an Igg4 anti-CCR5 under study for HIV that is now also being pursued for treatment of severe Covid-19.

Is anyone at TWiV aware of any trials looking at specifically maraviroc for decreasing the severity of Covid-19? And, could you help explain how both might work in modulating the immune response? Or directing me back to the podcast that discussed it… Curious on your thoughts and insights into these claims.

Thank you for your time, and podcasts,


Sharon Chi, DO, PGY 5

Infectious Diseases Fellow

George Washington University